Function – 6 ( MEP)

You have seen and operated several valves onboard ships. All the butterfly valve operation handles are operated by a locking arrangement because

Butterfly valves do not used gland packings and thus spindle doesn’t have anything to keep it in position and can open by vibration

Butterfly valve does have a spindle packing but same cannot be excessively tightened to have good grip on the spindle to prevent it from opening against vibration

Butterfly valves can move by vibration but that is not the main consideration, the main consideration being opening/closing against liquid pressure

All the butterfly valves do not have locking arrangement as there is no such requirement for the same

ANS.: C

Which of the group of method are used for priming of centrifugal pumps onboard ships?

Gravity tank, attached vacuum pump

Attached Vacuum pump, filling pump casing using a fresh water hose

Central priming system, attached vacuum pump, sea water priming

None of the above

ANS.: C

Which one of the following is a type of corrosion :-

Electroplating

Galvanisation

Graphitisation

Demulsification

ANS.: C

The size of solid particle contaminants in hydraulic systems is measured in:

Millimeter cubed

Nano-millimeter

Microns

Micro millimeter

ANS.: C

Pump Start But Motor gets overloaded or Trip on overload.

Alignment is wrong

Gland packing too tight

Worn out / Damaged ball bearing

Cavitations exists

All of the above

ANS.: A,B,C

Which of the following instruments measures propeller drop?

Poker Gauge

Telescopic feeler gauge

Trammel

Propeller drop gauge

ANS.: A

Which of the following can be done to reduce the cold corrosion of Main Engine cylinder liners using high sulphur fuel oil :-

Increasing cylinder oil feed rate

Using high TBN cylinder oil

Increasing scavenge air temperature

Decreasing cylinder oil feed rate

ANS.: B

Your ship has a OWS and reciprocating bilge pump of capacity 2.0 m3 /hr. It takes about 12 hours to pump out the complete bilge tank through OWS. The ship is going to dry-dock and Chief Engineer is recommending company to install a centrifugal pump of 10 m3 capacity which will take the same space and can pump out the bilge tank only in 2.5 hrs. The company should:

Accept the proposal as a centrifugal pump has several advantages over a reciprocating pump

There is no question of accepting a centrifugal pump as a Engine room bilge pump

Propose to fix a Gear pump instead of a centrifugal pump

Pipelines and pumps once designed cannot be changed as they are class approved

ANS.: B

Normally so called ???single screw pumps??? are used as sludge pumps in engine room. What is the correct technical name of these pumps?

Snake Pump

Screw Pump

Progressive cavity pump

Gerotor Pump

ANS.: C

In a Parallel-Gate type valve the sealing between the valve and the disc is provided by:

Appropriate tightening torque of the valve spindle

Gate and valve seat have a taper and when tightened they will seal against each other

Either the seat or the disc Gate are free-floating, allowing upstream pressure to seal the seat and disc against any unwanted leakage

For a gate type valve the sealing is never perfect and they always allow some leakage

ANS.: B

The crank web deflection readings of a diesel engine would be erroneous in which of the following conditions?

When the draught of the vessel has changed while readings were being taken

When cargo loading and discharging has been too rapid

When the crankcase temperature has changed substantially during the process of taking the readings.

None of the above

ANS.: 2,3

The purpose of an evaporator in the domestic refrigeration system is to

Transmit latent heat of evaporation

Absorb latent heat of fusion

Absorb latent heat of evaporation

Transmit latent heat of fusion

ANS.: C

Which of the following is an important requirement for proper functioning of sacrificial anode system :-

Good Insulation between anodes and ship???s hull

Good electrical continuity between anodes and ship’s hull

Providing protection of anodes from being painted over during hull painting

Presence of an insulating material between anode and the cathode

ANS.: B

The main disadvantages of a reciprocating pump over a Gear pump is that:

A gear pump is self priming while a reciprocating pump is not

Discharge of a gear pump is not affected by the direction of rotation while that of reciprocating pump is reversed

The discharge of reciprocating pump is pulsating and discharge rate is lesser

Reciprocating pumps are only available in high capacities and for smaller capacities only gear pumps can be used

ANS.: C

Which of the following types of damages are metal seatings of a valve subject to?Choose the correct alternative.

Corrosion, Erosion, Abrasion, Deformation

Corrosion, Fatigue failure, brittle fracture, caustic cracking

Erosion, caustic cracking, brittle fracture, Cloverleafing

None of the above

ANS.: A

You are pumping out sludge to a shore facility using your sludge pump. You find that the discharge rate of pump is very slow and suction filter is getting clogged frequently.What is the best alternative to counteract the problem?

Remove the pump suction filter and pump out the tank

Increase the tank temperature, keep an eye on the pump suction pressure and clean the filter as soon as it drops

As soon as the as the shore facility tells you that they are not receiving any sludge, you stop the pump and clean the filter

Fabricate a bigger mesh size suction filter and use in place of normal filter so that frequency of filter blockage is reduced and you can get a better discharge rate

ANS.: B

When centrifugal pump is used to pump a liquid of higher specific gravity the pump Power will

increase

decrease

Will not be affected as the pump power depends only on the flow capacity

None of the above

ANS.: A

The process of depositing zinc on steel surfaces by diffusion coating is known as :

Sherardising

Chromising

Calorising

Galvanising

ANS.: A

By which of the following is the attached vacuum pump of a ballast pump is driven?

Electrical motor

Hydraulic motor

Pump driven clutch

Pneumatically driven

ANS.: C

High tensile steels are :

High carbon steels with suitably added alloying elements

Medium carbon steels with suitably added alloying elements

Low carbon steels with suitably added alloying elements

None of the above

ANS.: C

After cleaning the sea chest filter you have placed the filter in the body and tightened the cover. Which one of the following is the best alternative?

You can open the filter inlet and outlet valves & directly start using the filter

If you do not want to use the sea chest in question, you need not worry and you can open the valves when required

Sea Water inlet valve should be crack opened, the filter body should be purged, any leakages and thereafter filter can be kept isolated or used as required

You will close the other side sea chest valves first and then open this side sea chest filter inlet and outlet valves

ANS.: C

Which of the following valves cannot prevent backflow of liquid in a pipeline?

Gate valve

Globe Check Valve

Swing Check Valve

Angle check valve

ANS.: A

Most steam traps respond well to cleaning. But when a thermodynamic trap fails to operate after cleaning, the next course of action should be:

Throttle the steam outlet valve

Renew the trap

Lap the disc and the seat of the trap

Throttle the steam inlet valve

ANS.: C

Which of the following option gives you the correct sequence of the metals in decreasing order of preferential corrosion when all of them are bonded and immersed in an electrolyte ?

About the author

Anand Gautam

Anand Gautam is a marine engineer, Graduated from M.E.R.I. Mumbai. He likes to sail onboard ship and is one who is passionate about his job. He loves to share his knowledge, information, and ideas to everyone in a simplified way just for his satisfaction.

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